(1) Field of the Invention
This invention relates to a rear cover for use in waterproof connectors and a process for forming a resilient sealing member molded in one piece in the rear cover.
(2) Description of the Related Art
Waterproof connectors are used for an electrical connection in various fields including motorcars and motorcycles. A waterproof connector is usually consisted of a connector body for making connection to a counter waterproof connector and a rear cover placed on the terminal insertion side of the connector body, which holds an electric wire connected to the terminal that is inserted in the connector body and prevents moisture from entering from the terminal insertion side of the connector body.
A waterproof connector shown in FIG. 8 is generally known and is disclosed in Japanese Patent Application Laid-Open No. H8-96883.
The waterproof connector 1 contains a male connector body 2, a female connector body 3 and a pair of rear covers 4 fitted to each terminal insertion side of the male connector body 2 and female connector body 3, in which a terminal (not shown in FIG. 8) connected to an electric wire 5 is mounted in the male connector body 2 and female connector body 3.
As shown in FIGS. 9 and 11, the rear cover 4 contains a rear cover body 8 made of synthetic resin and a resilient sealing member 9 made of waterproof rubber (for example, silicone rubber) molded in one piece in the rear cover body 8, in which each rear cover 4 is fitted to the corresponding rear of the male connector body 2 or female connector body 3 through a corresponding plate 7 having a hole 6 for the electric wire 5 to pass therethrough.
In the rear cover body 8, there are formed a base wall 10 (see FIG. 10) and a hood 11 (see FIG. 9) formed around the base wall 10. In the base wall 10, there are formed a pair of holes 12 (see FIG. 10) for an electric wire to pass through between inner and outer faces of the base wall 10 and a hollow holder pattern 14 (see FIG. 14) having a plurality of holes 13 (see FIG. 14). In the hood 11, there are formed a piece 15 and a hole 16 for the rear cover 4 to be fitted to the male connector body 2 or female connector body 3.
As shown in FIGS. 12 and 13, the resilient sealing member 9 contains a board-shape holder 17 formed by filling the holder pattern 14 with a waterproof rubber, a sealing body 19 extended from the holder 17, which has a pair of through holes 18 for the electric wire 5 to pass therethrough and protrudes toward an inner face side of the base wall 10, and a plurality of sealing lips 20 (three in FIGS. 12 and 13) formed around each through hole 18, in which a plurality of sealing lips 21 (two in FIGS. 12 and 13) are also formed around the sealing body 19.
The sealing lips 20 assure a seal between the electric wire 5 and the through hole 18. The terminal insertion side of the male connector body 2 or female connector body 3 is inserted between the sealing lip 21 and the hood 11 so that a waterproofing therebetween is assured.
The above plurality of holes 13 shown in FIG. 14 conducts a waterproof rubber into the inner face side of the base wall 10 when the holder pattern 14 is filled with the waterproof rubber.
In the above conventional waterproof connector, as shown in FIG. 8, the pair of rear covers 4 is fitted into each terminal insertion side of the male connector body 2 and female connector body 3 so that a waterproofing at each terminal insertion side portion is assured.
As shown in FIG. 17, a measure to solve the above problem is a split-type mold having such a structure that a pair of insertion parts 24 is inserted into a fixed mold 22xe2x80x2 so as to separate a mold for forming the hole 6 from a fixed mold for forming the remaining portion of the resilient sealing member 9 including the sealing portion of the sealing lips 20.
As shown in FIG. 15, the rear cover 4 is produced according to the following steps of: setting the rear cover body 8 in a fixed mold 22; tightening a movable mold 23 with the fixed mold 22; filling the holder pattern 14 with the waterproof rubber in order to mold the resilient sealing member 9 in one piece in the rear cover body 8; and loosening (shown in FIG. 16) the tightening force applied by the movable mold 23 (by moving the mold 23 toward a direction indicated by an arrow shown in FIG. 15) in order to release the molded rear cover 4 from the movable mold 23 (by moving the rear cover 4 toward a direction indicated by an arrow shown in FIG. 16). When the rear cover 4 is released from the mold, a large mold-release force is applied to the hood 11 through a press pin (not shown in the figures), causing a deformation and damage to the hood 11.
As shown in FIG. 15, since a difference between an outer diameter D1 of the movable mold 23 corresponding to the hole 6 (for the electric wire 5 to pass therethrough) and an outer diameter D2 of a sealing portion corresponding to the sealing lips 20 is large, the large mold-release force that may exceed an allowable stress of the hood 11 is needed in order to allow the portion having the outer diameter D1 to pass through the sealing portion having the outer diameter D2 when the rear cover 4 is mold-released. If a mold temperature is set to be high, the hood 11 made of synthetic resin is further easily deformed and damaged.
However, the following process for producing the rear cover 4 causes a deformation and damage to the hood 11 (see FIG. 9), by which are caused an imperfect fitting between the rear cover 4 and the connector bodies 2 and 3, and deterioration in the waterproofing quality.
As for the insertion parts 24 of the split-type mold, there are formed a base 24a that is fixed in the fixed mold 22xe2x80x2 and its contiguous portion 24b corresponding to the insertion hole 6, in which a taper 24c (outer diameter D3) corresponding to an inclination at the very end of the sealing lips 20 is formed at the end of the portion 24b. A movable mold 23xe2x80x2 has a portion 23xe2x80x2a (outer diameter D4) corresponding to the sealing lips 20, from which a portion corresponding to the insertion hole 6 is removed, resulting in that a difference between the two diameters of the mold becomes small (D3 being nearly equal to D4). Consequently, it is seemed that the mold-release force can be reduced and the deformation and damage of the hood 11 can be prevented from occurring.
However, according to the above split-type mold, in which the insertion parts 24 are inserted in the fixed mold 22xe2x80x2, disposing positions of the insertion parts 24 indicated by an arrow P in FIG. 18 interferes with a position of an injection inlet (for injecting the waterproof rubber therethrough) indicated by an arrow Q, resulting in that the above split-type mold is not practically useful as it is.
Nevertheless, an improvement in the above split-type mold is needed since it further has such an advantage that an action responding to wear of the mold (for example, prevention of a fin formation) is easily executed by replacing the insertion parts 24 in addtion to the aforementioned advantage of prevention of the deformation and damage of the hood 11.
It is therefore an object of the present invention to solve the above problem and to provide a rear cover that gives improvement in a property of mold-releasing and maintenance of a mold, and a process for forming a resilient sealing member molded in one piece in the rear cover.
In order to accomplish the above object, a first aspect of the present invention is to provide a rear cover, in which an electric wire is inserted through a base wall, having a hollow holder pattern on an outer surface of the base wall and a molded-in resilient sealing member containing: a holder formed in the holder pattern; a sealing body extended from the holder, which protrudes toward an inner side of the base wall and has a through hole for the electric wire to pass therethrough; and a plurality of sealing lips formed around the through hole, wherein a portion of periphery of the holder pattern is notched to form a hollow for injection inlet for molding the resilient sealing member in one piece in the rear cover.
In the rear cover according to the first aspect of the present invention, the hollow of injection inlet is formed at a portion of periphery of the holder pattern, thus improving a property of mold releasing and maintenance of a mold.
That is, even if a mold is provided with an insertion part to improve a mold-releasing property, the hollow of the injection inlet, thus formed, allows a separation between the insertion part and the injection inlet, thereby enabling an injection molding to be employed.
Consequently, according to the first aspect of the present invention, a deformation and damage of the rear cover can be prevented. In addition, an action responding to wear of the mold is easily executed and a fin formation can be prevented.
A second aspect of the present invention is to provide a process for forming a resilient sealing member in a rear cover comprising the steps of: forming the rear cover having a hollow holder pattern and a hollow of injection inlet contiguously formed by notching a portion of the periphery of the hollow holder pattern on an outer surface of a base wall; mounting the rear cover in a mold; and filling the hollow holder pattern with a rubber through the hollow of injection inlet, thereby a resilient sealing member containing: a holder formed in the holder pattern; a sealing body extended from the holder, which protrudes toward an inner side of the base wall and has a through hole for an electric wire to be inserted through the rear cover; and a plurality of sealing lips formed around the through hole, is molded in one piece in the ear cover.
According to the second aspect of the present invention, a deformation and damage of the rear cover can be prevented. In addition, an action responding to wear of the mold is easily executed and a fin formation can be prevented.